1. Field of the Invention
The present invention relates to special and novel probes, a gene amplifying method using cross (alternate) binding of the special probes, and a method of directly detecting a target gene and a method of detecting antigen/antibody using the gene amplifying method.
2. Description of the Related Art
In recent years, a method of amplifying a gene using a DNA polymerase, represented by a polymerase chain reaction method (hereinafter called the "PCR method"), a method of amplifying a gene by hybridizing polymer DNA having previously branched single-stranded DNA (hereinafter called the "branched DNA probe method"), and so on have been developed for detecting a very small amount of target gene.
The amplification of gene by the PCR method involves annealing hybridize) a primer complementary to a target gene (or a primer), and amplifying the gene through rise and fall of temperature using a thermostable DNA polymerase. Disadvantageously, this method takes a long time from amplification to detection of a gene, and is expensive. In addition, the amplification efficiency and specificity may vary depending on the design of a primer complementary to the target gene.
The amplification of gene by the branched DNA probe method, on the other hand, involves previously synthesizing a branched polymer single-stranded DNA probe, and hybridizing the branched polymer single-stranded DNA probe to a target gene to detect the target gene. However, the hybridization of the branched polymer single-stranded DNA probe to the target gene takes a long time because the branched DNA probe is a polymer. In addition, the branched polymer single-stranded DNA is limited in size, so that the detection of the target gene is also limited.